Dutasteride 0.5mg soft capsules box of 30 with blister strip of clear capsules

Dutasteride

How it works

Blocks both Type I and Type II 5-alpha reductase enzymes

Effect

Reduces DHT by up to 90% — stronger than Finasteride

From

£19.99

/month

This treatment option is subject to a consultation followed by clinical review.

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What is Dutasteride?

Dutasteride is a prescription medication that works similarly to Finasteride but is significantly more potent. While Finasteride blocks around 70% of DHT (the hormone causing male pattern baldness), Dutasteride blocks approximately 90% — making it the strongest DHT inhibitor available.

Originally developed and licensed as Avodart for treating enlarged prostate (BPH), Dutasteride is prescribed “off-label” for hair loss. While not officially licensed for this use in the UK, it’s widely prescribed by dermatologists and hair loss specialists who recognise its superior efficacy.

Dutasteride is typically recommended for men who haven’t achieved desired results with Finasteride, or who have more aggressive hair loss requiring stronger intervention.

How effective is Dutasteride?

Clinical studies show Dutasteride outperforms Finasteride for hair count and thickness. It provides the most complete DHT suppression available, making it the strongest option for men with aggressive hair loss:

  • Dutasteride reduces serum DHT by approximately 90%, compared to 70% with Finasteride — providing significantly more complete protection for hair follicles.
  • In a head-to-head trial, Dutasteride 0.5mg produced significantly greater hair counts than Finasteride 1mg after 24 weeks — most notably at the crown area.
  • Its long half-life (4-5 weeks vs 6-8 hours for Finasteride) provides more consistent DHT suppression, even if you occasionally miss a dose.

Dutasteride is typically recommended as a step-up treatment for men who haven’t achieved adequate results with Finasteride after 12+ months.

Slim man and a heavier man standing back to back, showing different body shapes

How does Dutasteride work?

Like Finasteride, Dutasteride works by blocking the enzymes that convert testosterone to DHT. The key difference is that Dutasteride blocks both enzyme types, not just one.

This dual-action approach provides the most complete DHT suppression available. Here’s what that means for you:

01

Blocks both enzyme types: Unlike Finasteride (Type II only), Dutasteride inhibits both Type I and Type II 5-alpha reductase enzymes. Since both types contribute to DHT production in the scalp, this provides more complete suppression.

02

90% DHT reduction: Dutasteride reduces serum DHT by approximately 90%, compared to 70% with Finasteride. This greater suppression can be crucial for men with aggressive hair loss who need maximum follicle protection.

03

Long-lasting effect: Dutasteride has a very long half-life (4-5 weeks vs 6-8 hours for Finasteride). This means it stays in your system longer and provides more consistent DHT suppression, even if you occasionally miss a dose.

04

Off-label but proven: While not officially licensed for hair loss in the UK, Dutasteride is widely prescribed by dermatologists and hair loss specialists. It’s licensed for hair loss in Japan and South Korea, and off-label prescribing is a well-established practice in medicine.

05

Combine for maximum results: For the strongest non-surgical approach to hair loss, some men combine Dutasteride with topical Minoxidil. Dutasteride addresses the root cause (DHT) while Minoxidil stimulates follicles directly.

Smiling woman with curly hair in a turquoise vest top exercising outdoors in the sunshine
Smiling woman with curly hair in a turquoise vest top exercising outdoors in the sunshine

Who is eligible for Dutasteride?

Dutasteride is a prescription treatment typically recommended for men who need a stronger approach to hair loss — particularly those who haven’t achieved desired results with Finasteride.

Here’s what’s involved:

  • Eligibility: You must be a man aged 18 or over with male pattern baldness. Dutasteride is typically considered after Finasteride hasn’t produced adequate results, or for aggressive hair loss.
  • Off-label use: Dutasteride is prescribed off-label for hair loss. You should understand this means it’s not officially licensed for this purpose in the UK, though it’s widely used by specialists.
  • Long-term commitment: Like Finasteride, Dutasteride works best as a continuous treatment. Stopping will cause DHT levels to gradually return to normal over 3-6 months.
  • Assessment process: You’ll complete an online questionnaire about your health, hair loss history, and previous treatments.
  • Clinical review: A Trimu clinician will review your answers, including your response to previous treatments, to decide if Dutasteride is the right step up for you.

Who shouldn’t use Dutasteride?

Dutasteride isn’t suitable for everyone. It should not be used if you:

  • Are female — Dutasteride can cause severe birth defects. Women must NEVER handle opened or damaged capsules.
  • Are under 18 years old.
  • Have liver disease.
  • Are allergic to Dutasteride, Finasteride, or any of its ingredients.
  • Have prostate cancer or abnormal PSA levels.
  • Experienced side effects on Finasteride.
  • Plan to donate blood (wait 6 months after stopping).

Instructions

How to take Dutasteride

Taking Dutasteride is simple — it’s one soft capsule taken once a day, with or without food. Swallow the capsule whole with water. Do not chew, crush, or open the capsule as the contents may irritate your mouth and throat. Due to its long half-life, missing the occasional dose is less critical than with Finasteride — just continue as normal.

Step-by-step Instructions

Step 1

Take one capsule daily

  • Take one 0.5mg soft capsule every day, at roughly the same time each day.
  • Swallow the capsule whole with water. Do NOT chew, crush, or open — the contents may irritate your mouth and throat.
  • You can take Dutasteride with or without food — it doesn’t affect absorption.

Step 2

Be patient with results

  • You may experience temporary increased shedding as follicles reset — this is normal and indicates the treatment is working.
  • Hair loss typically stabilises within 3-6 months. Visible improvement in density and thickness is usually noticeable by 6-12 months.
  • Peak improvement is typically seen by year 2. Continue treatment to maintain results.

Step 3

Important considerations

  • Tell your doctor you take Dutasteride before any PSA test — it lowers PSA readings and could mask prostate issues.
  • You must wait 6 months after stopping Dutasteride before donating blood, due to its long half-life.
  • Because Dutasteride stays in your system for weeks, side effects may take longer to resolve after stopping compared to Finasteride.

Step 4

If you miss a dose

  • Due to Dutasteride’s long half-life (4-5 weeks), missing the occasional dose is less critical than with Finasteride.
  • Simply take your next dose as normal. Don’t double up to compensate.
  • Store capsules at room temperature, away from moisture and direct sunlight.

FAQs

Things you should know about Dutasteride

Dutasteride is licensed for hair loss in some countries (Japan, South Korea), but not in the UK or US. The manufacturer chose not to pursue an additional licence — likely because Finasteride already dominates the market. However, doctors can legally prescribe it “off-label” when they believe it’s the best option for a patient. Off-label prescribing is common and well-established in medicine.

Generally, yes. Finasteride is the standard first-line treatment — it’s licensed specifically for hair loss, has a longer track record, and works well for most men. Dutasteride is typically recommended if Finasteride hasn’t produced adequate results after 12+ months, or if you have particularly aggressive hair loss. Starting with the less potent option makes sense for most people.

Switching is straightforward — simply stop Finasteride and start Dutasteride the next day. There’s no need for a washout period. Because Dutasteride has a very long half-life, it will gradually build up in your system. You may experience some shedding during the transition as your body adjusts to the stronger DHT suppression.

The types of side effects are the same, but studies suggest they may be slightly more common with Dutasteride due to greater DHT suppression. In clinical trials for BPH, sexual side effects occurred in approximately 4-5% of Dutasteride users vs 2-3% for Finasteride users. However, most men tolerate Dutasteride well. If you experienced side effects on Finasteride, you may be more likely to experience them on Dutasteride.

Dutasteride can cause birth defects if a pregnant woman receives contaminated blood. Because of its very long half-life (4-5 weeks), you must wait 6 months after stopping Dutasteride before donating blood. This ensures the medication has been completely eliminated from your system. Finasteride has a similar restriction but only requires a 1-month wait.

Because of its long half-life, DHT levels return to normal more slowly than with Finasteride — typically over 3-6 months. Hair loss will eventually resume and any regrown hair will gradually be lost. Most men who respond well to Dutasteride continue taking it indefinitely to maintain results.

Yes, this combination is often recommended for maximum results. Dutasteride blocks DHT systemically while Minoxidil stimulates hair follicles directly. The two treatments work through different mechanisms and complement each other well. Many dermatologists consider this the most effective non-surgical approach to hair loss.

Side effects are similar to Finasteride but may be slightly more common due to greater DHT suppression. Uncommon effects (1-5%) include decreased libido, erectile difficulties, reduced ejaculate volume, and ejaculation disorders. These often improve with continued use and typically resolve after stopping. Rare effects include breast tenderness or enlargement, testicular pain, depression, and allergic reactions. Because Dutasteride stays in your system for weeks, side effects may take longer to resolve after stopping compared to Finasteride. Tell your doctor you take Dutasteride before any PSA test.

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Why you can trust Trimu

Regulated care from a registered UK pharmacy

Safe, discreet treatment — reviewed by qualified clinicians and dispensed by our own UK-registered pharmacy.

Registered UK pharmacy

Dispensed by a GPhC-registered UK pharmacy (premises 1037748).

Reviewed by registered clinicians

GMC-registered doctors and GPhC-registered pharmacists check every case before any treatment is approved.

Discreet, ongoing support

Free, discreet delivery and clinical support throughout your treatment.

Our mission

Trimu began with a simple belief: getting safe, effective treatment shouldn’t be expensive, complicated, or embarrassing. We pair UK-registered clinicians with our own regulated pharmacy to offer honest advice, fair prices, and genuinely discreet care — so you can get on with feeling better.